The present invention can for example be implemented for an actuator comprising an electronically commutated brushless direct-current motor (or also called <<BLDC>>, acronym for BrushLess Direct Current). A motor of this type comprises a rotor provided with permanent magnets and a stator provided with several windings.
The motor further comprises a control system arranged to successively supply the windings with electrical energy. For the motor to operate, the electromagnetic field generated by the successive supply to the windings should be synchronized to the position of the rotor.
To this end, the control system comprises position sensors arranged to determine the position of the rotor.
This type of motor can be regulated according to its rotational speed. It is thus possible to limit the speed such that the rotational speed does not exceed the maximum speed permissible by the mechanical members of the actuator.
This type of motor can also be regulated according to its torque. It is thus possible to limit the torque such that the torque does not exceed the maximum torque permissible by the mechanical members of the actuator.
This system is satisfactory when all the members of the motor operate properly. However, the actuator, and in particular the motor, needs to be protected since there is, in particular, always a risk that the current applied to the motor demagnetizes the permanent magnets, that a short circuit is formed, in particular during the supply change to the windings, or that the torque applied to the motor abnormally increases.